Differences of Subgingival Microbiota between Young and Elder Rhesus Macaques

Objectives: The rhesus macaque serves as an animal model to study HIV infection and periodontitis.  Previously, we determined that the oral microbiome of the macaque is distinct, albeit similar, to that of the human.  The purpose of this study is to determine similarities between the subgingival plaque of younger vs older animals, who are subject to oral disease.  Methods: Bacterial DNA was isolated from subgingival plaque from 5 young animals (<5 years) and 4 older animals (>12 years), and PCR-amplified using broad range 16S rDNA bacterial primers.  Full-sized amplicons of about 1500 bp were cloned and subsequently sequenced to generate phylogenetic trees for species identification. Results: Based on the analysis of 900 clones, there were 48 predominant species, of which 27 were unique to the macaque.  The remaining species were identified as “human” species.  The most commonly-detected species found in subgingival plaque were Abiotrophia defectiva, Gemella morbillorum  (macaque specific), Streptococcus mitis bv2, and a Lachnospiraceae phylotype.    Species of Actinomyces, Veillonella, Eubacterium and related spp., and Prevotella, typically detected in humans, were notably absent in younger monkeys, but present in the older monkeys.   Conclusions:  The oral microbiome of the subgingival plaque of the rhesus macaque is distinct from that of humans.  Although some macaque species are also found in humans, most are unique to the monkey.  Bacterial profiles of subgingival plaque are age-dependent, with more “typical” periodontal pathogens present in older monkeys.  These findings help to validate using the macaque monkey as a model for human disease. Supported by DE020025.

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